Heat exchanger



Sept. 20, 1966 T. F. PAULS 3,273,637

HEAT EXCHANGER Original Filed June 5, 1957 2 Sheets-Sheet 1 FIGI FIG. 2FIG. 5

IN V EN TOR.

THERON F. PAULS ATTORNEY Original Filed June 5, 1957 2 Sheets-Sheet 2FIGS IN VEN TOR.

TH ERON F. PAULS ATTORNEY United States Patent Office 3,273,637 PatentedSept. 20, 1966 3,273,637 HEAT EXCHANGER Theron F. Pauls, Oak Park, Ill.,assignor to Olin Mathieson Chemical Corporation, New York, N.Y., acorporation of Virginia Original application June 3, 1957, Ser. No.663,062, now Patent No. 2,999,308, dated Sept. 12, 1961. Divided andthis application Oct. 5, 1960, Ser. No. 67,147 5 Claims. (Cl. 165-171)This application is a division of co-pending application Serial No.663,062, filed June 3, 1957, now Patent No. 2,999,308, issued September12, 1961.

This invention relates to a heat exchanger construction and moreparticularly to the art of manufacturing a multiple parallel tube typeof heat exchanger unit.

A commonly used and effective type of heat exchanger construction forevaporators, air conditioners, condensers, internal engine coolingradiators, such as automobile radiators, or for space heating such assteam radiators, and the like, is formed of sheet metal and includes anumber of conduits generally in a parallel spaced arrangement extendingfrom a first or intake header to a second or outlet header. One or moreof such sheet metal units may be employed; and the conduits or tubesserve to carry within a confined heat exchange medium such as water,steam, refrigerant coolant, or the like, in conductive relationship withanother medium such as air or other gas passing between the tubes. Thistype of construction fabricated from sheet metal is typical ofautomobile radiators, for example, where the heated water issues fromthe cooling block of the engine with the aid of a pump, first enters oneof two headers, and then thru a great number of thin-walled, relativelyfiat, closely spaced tubes between which cooling air is blown and whichextend usually vertically from one to the other headers. Condensers arealso frequently of this same type of construction.

According to one heretofore known method of manufacture illustrated inUS. Patent 2,690,002, this type of heat exchanger uni-t may be readilymanufactured to provide a great multiplicity of tubes in a sheet ofmetal.-

This method involves emplacement of a suitable predetermined pattern ofweld preventive between component sheets, pressure welding in alladjoining areas except at the preventive, and inflation along'thepreventive to erect tubes integral with the resultant tubed plate.vantage heretofore has not been taken of this method inasmuch as thetubes formed are of rather flat or oval shape with the major dimensionslying within or parallel to the metal plate in which the tubes areformed. In

an improved heat exchanger core structure having closely spaced sheetmetal elements containing both advantageously angled tubes and alsointegral extended secondary surfaces or fins and all of a constructionadapted for the most economical mass production methods of assemblingthe core. Other objects and advantages will be apparent and theinvention will be better understood from the following description whenread with reference to the accompanying drawing, in which:

FIGURE 1 is a perspective view of a portion of a typical pressure weldedblank made according to the aforementioned US. Patent 2,690,002 andillustrating a preliminary construction from which the finished units ofthis invention may be mostreadily and advantageously fabricated;

FIGURE 2 is a perspective view of an adjoining fragment of the sheetmetal unit in a subsequent stage of fabrication still according to theaforementioned prior art patent;

FIGURE 3 is a perspective view of another adjoining fragment of the unitprocessed in accordance with one embodiment of this invention to providea new and improved tube shape;

FIGURE 4 is a transverse cross sectional view corresponding to the endview of FIGURE 1 but showing another embodiment in accordance with thisinvention;

FIGURE 5 is a transverse cross sectional view showing another partiallylaminated sheet blank at a preliminary stage according to the invention;

FIGURE6 is another transverse cross sectional view showing a later stageof manufacture of the embodiment of FIGURE 5;

FIGURE 7 is a side elevational view of a portion of the embodiment ofFIGURES 5 and 6 shown in still further progressive stages of manufactureshowing the full development of one form of fin structure;

FIGURE 8 is a side elevational view of the upper portion of anotherembodiment of the form of a panel Full admany applications it is desiredthat the tubes extend not greater number of the tubes in spaced parallelrelationship rather than a lesser number in the same plane. This designadapts the units to fabrication as single pieces of large size, a lessernumber of which may then be put together for installations where theexternal medium passes through perforations of the plate transversely toit rather than passing parallel to the plate along its surfaces.

Therefore, it is an object of this invention to provide a novel andimproved heat exchanger unit free from the aforementioned disadvantagesof complex and consuming constructions and a new and improved method ofconstructing the same. A further object of this invention is to providea heat exchanger unit in which a great number of fluid conduits areintegrated into a single structural member relatively free from seamsand joints and hence a unit admirably suited to mass production methods.Another object of this invention is to provide including a header; and

, FIGURE 9 is a fragmentary cross sectional plan view taken on lineIX-IX of FIGURE 8.

In accordance with this invention blank sheet metal panels or plateshaving relatively shallow passageways and intervening webbing aresubjected to a reduction in thickness,such as by swaging, between thepassageways in such a manner as to reshape the passageways to more fullyextend them out of the plane of the sheet. The resultant tubes are ofrelatively oblong shape extending at right angles to the heat exchangepanel from which the tubes are formed integrally along the panel.Reshaping is accomplished by a swaging, coining or forging operationwhich thins the metal between the tubes and narrows the dimension of thetubes or passageways in the plane of the panel or sheet while at thesame time tending to extendthe dimension of the tube protruding beyondor out of the plane of the panel, but without any attendant reduction inthe overall width of the initial blank. As a result the major axis ofthe tube cross section is put at an angle of about The panel ispreferably of the type obtained in accordance with the teachings of theaforementioned US. Patent 2,690,002 wherein the passageways in embryonicform are defined by an included thin layer or stratum of weld preventingmaterial such as graphite or the like. For the purpose of providingintegral fins closely and most advantageously associated with the tubes,the pressure welded panels also include preferably an interveningunwelded area defined by weld preventive extending between the tubeforming laminated portions but spaced therefrom. This interveningunbonded area is subjected to the aforementioned thinning and may lie inone or 3 more strata to provide two or more thin fins to give a verylarge extended secondary heat exchanger surface. The transverse air ductperforations together withfins are constructed in accordance with thisinvention by first piercing the sheet in the webbing between the tubes,but preferably in the vicinity of the thinned intervening unweldedportions at spaced intervals up and down in the are-a between adjacenttube portions of the sheet. Finally, an extrusion piercing andseparating step is accomplished along the intervening unwelded stratumin the sect-ions remaining after the first slitting or piercingoperation so as to separate and twist the fins to put them in the bestheat exchange relationship at an angle to the face of the plate. Theswaging, piercing and separating operation of this invention has beenfound to produce an advantageous disposition of the tubes and also avery thin fin structure between the tubes. The fins are turned so as tobe in desired alignment or feathering with respect to the airflow. Theresultant additional fins are many times thinner and have a greatlymultiplied effective area as compared to a single heavy fin.

Where a more greatly extended fin surface is desired a severe extrusionis effected in the piercing operation in the intervening fin area so asto not only thin but also further extend the fins out of the plane ofthe heat exchanger plate.

Each of the resultant plates or units may be used alone or stacked upwith a plurality of like plates to form a heat exchanger core structureof the multiple tube type where the tubes of one plate are staggeredwith respect to the tubes of an adjacent plate and where the tubes ofeach plate are justaposed opposite the fins of an adjacent plate.

Internal layers of weld preventative such as graphite have been found tofacilitate the thinning and tube reshaping.

In FIGURE 1 there is shown a preferred form of blank 1 suitable forpractice of this invention. It is characterized by a pattern 2 includingcertain unjoined portions between the outer faces of the blank 1 whereatthe blank is laminated so as to include spaced parallel parted orlaminated portions 3 and also intervening and surrounding portions 4 atwhich the blank remains unparted. As

, shown in FIGURE 2, the parted portions 3 are adapted for developmentby fluid inflation of internal passageways 6 forming part of apreliminary conduit system 9 evidenced by corresponding rather shallowbulges 7 and 8 on the surface of the intermediate product 5. Althoughinflation involving the admission of fluid under pressure to theinterior surfaces at the lamina 3 which forces these apart to produce apreliminary distention along the internal passageways 6 is contemplatedas a preferred mode of passageway .generation, other flat passagewaycontaining blanks are also contemplated. In any event, unparted portions4 remain undistended and separate the passageways not only from eachother but also from any intervening opening in the blank.

FIGURE 3 shows the new finished article resulting when the intermediateproduct is worked in accordance with the invention to reduce thethickness of the metal at web 14 driving the metal to narrow theoriginal passage 6 in the plane of the blank while elongating it toprotrude on one side at 17 and on the opposite side at 18 so that thefinished panel contains a finished system of hollows 19 having oblongtube passages 16 disposed transversely to extend out the plane of thepanel considerably beyond the preliminary bulges 7 and 8. At the thinnedweb 14 the panel has been stiffened by work hardening. The swagingoperation preferably compresses the metal most severely at the centralpart of the web 14 so as to force the metal to flow more readily asshown. Accordingly, the thickness of the web is less, in gradationsthroughout the cross-sectional extent thereof, than the thickness ofportions of the panel circumscribing the passages 16.

In the embodiment of FIGURE 4 the panel web is indented andsimultaneously cut to form an air duct 24 between the oblong tubes 26while forming the conduit system 29 of the panel having protuberances 27on one side as the leading edge of the tubes and protuberances 28 on theopposite side as the trailing edge.

In FIGURE 5, another form of roll forged blank 31 is shown also havinginternal separations in spaced parallel relationshipat 33 at which thepassageways 46 are to be erected and reshaped to the perpendicularconfiguration seen in the intermediate hollow article shown in FIGURE 6which is ready for finning. The blank 31 differs from the previous blankchiefly by the inclusion of two strata 35 and 36 of separation in theblank portion 34 intervening the separations at 33 and isolatedtherefrom by the unparted areas 32.

After the blank 31 is forged to the shape shown in FIGURE 6, which ischaracterized by protruding tube extremities 47 and 48 and by thereadily separable zones 45 and 46, it is then provided with a series ofslits such as 50 in the web 44 running athwart the tubes 47 and themetal remaining between the slits is twisted and preferably alsoextruded to form the almond shaped openings 55 and transverselyextending crude fin 54 struck up out of the panel to extend at anydesired angle with it, such as an angle of 90. Finally, laminations 45and 46 of each preliminary fin 54 are opened up to form three finishedfins 56, 57 and 58 each very thin and also turned at an angle to thefinished panel now having air ducts 61 and 62 and also 63 and 64 inplace of each of the single openings 55.

It will be understood that while three very thin fins are shown in thisembodiment, each fin portion can remain whole or be subdivided into anynumber .of individual fins such as the two shown for example in theembodiment of FIGURE 8 where the panel 71 has many parallel tubes 77,many sets of fins 76 and 78, and also has main openings 75 together withfin openings 79. One end of the panel has a connecting header 72 and asupply or discharge connection 80 which is preferably cut free at 82 and83 from the surrounding panel and rounded to permit coupling with asupply or discharge line such as 102 shown in the assembled core ofFIGURE 9.

The heat exchange core consists of a series of panels 71, 81 and 91fastened together and mounted by any suitable means such as fastener 105mounting the unit on support member 106. The individual tubes 77 ofpanel 71 are in staggered relationship with the tubes 87 of panel 81;and the tubes 97 of adjacent panel 91 in turn are staggered with respectto tubes 87. Thus fins 76 and 78 of panel 71 and its openings Y75 and 79are aligned with a tube 87 of panel 81 as well as with the openings andfins 96 and 98 of panel 91. Suitable coupling is made between therespective panel connections 80, and 100 and pipes such as 102 and 103,for example.

Since many other embodiments may occur to those skilled in the art it isto be understood the foregoing -is intended by way of illustration of anembodiment now believed preferred and not as a limitation of the scopeof the present invention except as set forth in the appended claims.

What is claimed is:

1. A hollow sheet metal plate having extending internally therein asystem of fluid passages with said passages comprising spaced parallelfluid passageways extending longitudinally in said plate and alsodistended out of the plane of said plate with the distention of saidpassageways in a cross-section thereof normal to said plane extendingout of said plane an .amount greater than the width of said passageways.in said cross-section so that said passageways in said. cross sectionare elongated to have their major axis extending in a directiontransverse said plane, the thickness of said plate between saidpassageways being less, in gradations throughout the crosssectionalextent thereof, than the thicknessof saidv plate in portionscircumscribing said passageways, a portion of said plate between saidpassageways having at least one opening through said plate adjacent atleast one integral fin extending out of and substantially transversesaid plane of said plate.

2. A plate according to claim 1 wherein said portion of said platebetween said passageways is provided with a series of openings throughsaid plate in alternation with integral fins extending out of andsubstantially transverse said plane of said plate.

3. An assembly comprising a plurality of the plates of claim 2 disposedin face-to-face relationship with the passageways of one of said platesopposite to end extending in substantially the same direction as the webportion, between adjacent passageways, of an adjacent similar plate.

4. The assembly of claim 3 wherein each of said plates includes a headerextending internally of said plates in a direction transverse to andinterconnecting therein said passageways, and an interconnection betweenthe headers in the assembly of said plates.

5. The plate of claim 3 including a fluid passage extending internallythrough said fins in a direction transverse said plane.

References Cited by the Examiner ROBERT A. OLEARY, Primary Examiner.

HERBERT L. MARTIN, Examiner.

E. F. BLANCHARD, T. W. STREULE,

Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noa3,273,637 September 20, 1966 Theron Fm Pauls that error appears in theabove numbered pat- It is hereby certified d that the said LettersPatent should read as ent requiring correction an corrected below.

Column 5, line 13, for "end" read and -D Signed and sealed this 22nd dayof August 1967.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

1. A HOLLOW SHEET METAL PLATE HAVING EXTENDING ENTERNALLY THEREIN ASYSTEM OF FLUID PASSAGES WITH SAID PASSAGES COMPRISING SPACED PARALLELFLUID PASSAGEWAYS EXTENDING LONGITUDINALLY IN SAID PLATE AND ALSODIDTENDED OUT OF THE PLANE OF SAID PLATE WITH THE DISTENTION OF SAIDPASSAGEWAYS IN A CROSS-SECTION THEREOF NORMAL TO SAID PLANE EXTENDINGOUT OF SAID PLANE IN AN AMOUNT GREATER THAN THE WIDTH OF SAIDPASSAGEWAYS IN SAID CROSS-SECTION ARE ENLONGATED SAID PASSAGEWAYS INSAID CROSS-SECTION ARE ENLONGATED TO HAVE THEIR MAJOR AXIS EXTENDING INA DIRECTION TRANSVERSE SAID PLANE, THE THICKNESS OF SAID PLATE BETWEENSAID PAS-